Morphology Of Nanostructures Research Articles

Exosomes from porcine serum as endogenous additive maintain function of boar sperm during liquid preservation at 17 °C in vitro

The supplementation of sperm culture media with serum is quite common, and improves both sperm survival and motility. However, the link between serum and sperm remains poorly understood. The present study is the first investigation of the effects on sperm quality and function of endogenous porcine serum exosomes in medium used for culturing boar sperm. Scanning electron microscopy (SEM) confirmed that serum-derived exosomes from both castrated boars (cbsExos) and sows (ssExos) exhibited typical nanostructural morphology and expressed CD63, CD9, and Alix, as shown by Western blotting. At 17 °C, the progressive motility and membrane integrity of sperm were significantly increased after incubation of fresh boar semen for 7 days with cbsExos-4 (8 × 1010 particles/mL) or ssExos-16 (32 × 1010 particles/mL). Moreover, cbsExos-4 and ssExos-16 were found to be effective sperm additives, improving mitochondrial transmembrane potential (ΔΨm) and adenosine triphosphate (ATP) content, total antioxidant activity (T-AOC), superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity while reducing reactive oxygen species (ROS) levels, and malondialdehyde (MDA) content following preservation at 17 °C after a 5-day incubation. Both fluorescence and SEM showed that the serum exosomes bound directly to the sperm membrane, suggesting an interaction that could influence sperm-zona pellucida binding. Overall, this study provides new insights into the potential benefits of adding cbsExos and ssExos to enhance the quality of boar sperm during ambient temperature preservation, which may lead to advancements in sperm preservation strategies.

Recent Research Trends for Metal Oxide Nanostructures Based Chemoresistive Gas Sensors

In the modern era, advanced industrial and process technologies in various fields are known to produce harmful gases. These gases typically leak at low concentrations, but continuous exposure can cause serious harm to health and safety. Since human sensory organs cannot detect these risks or leaking hazardous gases, there has been significant interest in developing high-performance gas sensors capable of rapidly detecting harmful and hazardous gas leaks. Metal oxides possess several advantages for such applications, including ease of manufacturing, affordability, and high sensitivity to harmful gases. In this review, we highlight recent progress in the field of chemo-resistive gas sensors based on metal-oxide nanostructures. It begins by discussing the features of various nanostructure morphologies such as 0-dimensional nanospheres to nanocomposites of nanowires. It then describes methods for fabricating metal-oxide nanostructures. Finally, we describe recent advances in the design and fabrication of nanostructures for metal-oxide gas sensors using four different morphologies: 0-dimensional (0 D, nanosphere and nanoparticle), 1-dimensional (1 D, nanowire and nanorod), 3-dimensional (3 D, nanoflower and nanocomposite), and heterojunctions. Based on their morphology-dependent sensing properties, there are various fields of application for gas sensors, with different target gases. This review can serve as an overview of recent research trends and offer insights into the future development of next-generation high-performance gas sensors.

Study of the antimicrobial activity of zinc oxide nanostructures mediated by two morphological structures of leaf extracts of Eucalyptus robusta Sm

The growing microbial resistance against antibiotics and the development of resistant strains has shifted the interests of many scientists to focus on metallic nanoparticle applications. Although several metal oxide nanoparticles have been synthesized using green route approach to measure their antimicrobial activity, there has been little or no literature on the use of Eucalyptus robusta Smith aqueous leaf extract mediated zinc oxide nanoparticles (ZnONPs). The study therefore examined the effect of two morphological nanostructures of Eucalyptus robusta Sm mediated ZnONPs and their antimicrobial and antifungal potential on some selected pathogens using disc diffusion method. The samples were characterized using Scanning and Transmission Electron Microscopy, Energy-Dispersive Spectroscopy and Fourier Transform Infrared Spectroscopy. From the results, the two ZnO samples were agglomerated with zinc oxide nanocrystalline structure sample calcined at 400 °C (ZnO NS400) been spherical in shape while zinc oxide nanocrystalline structure sample calcined at 60 °C (ZnO NS60) was rod-like. The sample calcined at higher temperature recorded the smallest particle size of 49.16 ± 1.6 nm as compared to the low temperature calcined sample of 51.04 ± 17.5 nm. It is obvious from the results that, ZnO NS400 exhibited better antibacterial and antifungal activity than ZnO NS60. Out of the different bacterial and fungal strains, ZnO NS400 sample showed an enhanced activity against S. aureus (17.2 ± 0.1 mm) bacterial strain and C. albicans (15.7 ± 0.1 mm) fungal strain at 50 mg/ml. Since this sample showed higher antimicrobial and antifungal activity, it may be explored for its applications in some fields including medicine, agriculture, and aquaculture industry in combating some of the pathogens that has been a worry to the sector. Notwithstanding, the study also provides valuable insights for future studies aiming to explore the antimicrobial potential of other plant extracts mediated zinc oxide nanostructures.

Polarization-Dependent Anisotropy of LIPSSs' Morphology Evolution on a Single-Crystal Silicon Surface.

Utilizing the principle of laser-induced periodic surface structures (LIPSSs), this research delves into the morphological evolution of single-crystal silicon surfaces irradiated by a near-infrared picosecond laser through a scanning mode. With the increase in laser energy density, the nanostructure morphology on single-crystal silicon surfaces induced by incident lasers with different polarization directions sequentially produces high spatial-frequency LIPSSs (HSFLs) with a period of 220 nm ± 10 nm parallel to the laser polarization, low spatial-frequency LIPSSs (LSFLs) with a period of 770 nm ± 85 nm perpendicular to the direction of the polarization, and groove structures. Furthermore, by varying the angle between the laser polarization and the scanning direction, the study examined the combined anisotropic effects of the laser polarization scanning direction angle and the laser polarization crystal orientation angle on the genesis of LIPSSs on single-crystal silicon (100) surfaces. The experiments revealed polarization-related anisotropic characteristics in the morphology of HSFLs. It was found that when the polarization angle approached 45°, the regularity of the LSFLs deteriorated, the modification width decreased, and the periodicity increased. This is critical for the precise control of the LSFLs' morphology.

Niobium-Based Oxide for Anode Materials for Lithium-Ion Batteries.

Recently, it has become imperative to develop high energy density as well as high safety lithium-ion batteries (LIBS) to meet the growing energy demand. Among the anode materials used in LIBs, the currently used commercial graphite has low capacity and is a safety hazard due to the formation of lithium dendrites during the reaction. Among the transition metal oxide (TMO) anode materials, TMO based on the intercalation reaction mechanism has a more stable structure and is less prone to volume expansion than TMO based on the conversion reaction mechanism, especially the niobium-based oxide in it has attracted much attention. Niobium-based oxides have a high operating potential to inhibit the formation of lithium dendrites and lithium deposits to ensure safety, and have stable and fast lithium ion transport channels with excellent multiplicative performance. This review summarizes the recent developments of niobium-based oxides as anode materials for lithium-ion batteries, discusses the special structure and electrochemical reaction mechanism of the materials, the synthesis methods and morphology of nanostructures, deficiencies and improvement strategies, and looks into the future developments and challenges of niobium-based oxide anode materials.

Controllable fabrication of Sub-20nm structures with coupling field tip enhancement effect induced by nanosecond pulsed laser irradiation

The nanofabrication technique using nanosecond pulsed laser irradiated probes still faces challenges in achieving controllable processing of nanostructure morphology and feature size, as well as a lack of comprehensive understanding regarding the underlying mechanisms involved in nanostructuring. This study used AFM probes irradiated with nanosecond pulsed lasers to realize controllable processing of nano-lines and nanopatterned structures on metal surfaces by adjusting the tip-sample distances. The controllable capability of the tip-sample distance in influencing the morphological characteristics and feature sizes of nanostructures has been demonstrated, which can be simultaneously characterized by AFM and SEM. The minimum lateral feature size down to 16.65 nm, while the maximum depth is 16.99 nm. Numerical modeling using FEM reveals the simultaneous presence of physical fields, including optical, electromagnetic, thermal, and mechanical near the tip. The essential nanostructuring mechanism involves depositing surface coupling energy onto materials, which induces local thermal energy and enables the removal of material. Different surface coupling energies can be induced by varying the tip-sample distance, which theoretically demonstrates the controllable processing of nanostructure morphology and feature size in experiments. This study highlights the potential application of regularly arranged carbon nanotubes faced by carbon nanotube device fabrication.

Self‐assembly and degradation of photolabile diblock bottlebrushes

AbstractAqueous self‐assembly of amphiphilic block copolymers form diverse nanostructured morphologies depending on block volume fraction and solvophilicity. Stimuli‐responsive motifs have been combined with self‐assembled micelles to afford spatiotemporal, on‐demand encapsulation and payload release. However, the role of modular polymer architecture (i.e., bottlebrushes) in stimuli‐responsive aqueous self‐assembly is not fully understood. The synthesis, aqueous self‐assembly, and photoirradiation of photolabile, amphiphilic bottlebrush block copolymers is presented herein. Specifically, the efficient photoscission of o‐nitrobenzene motifs at the junction of a poly(norbornene o‐nitrobenzene polystyrene)‐block‐poly(norbornene polyethylene glycol) diblock bottlebrush side chain and backbone cleaved away hydrophobic polystyrene side chains and artificially increased the volume fraction of poly(ethylene glycol) (fPEG). In doing so, self‐assembled micelles readily degrade to micelle‐to‐micelle and micelle‐to‐aggregate structures after photoirradiation. Finally, this bottlebrush micelle system is used to demonstrate the efficient encapsulation and stimuli‐responsive release of Nile Red that is monitored by fluorescence spectroscopy and dynamic light scattering. The contribution of this work expands the utility of amphiphilic bottlebrush systems as highly efficient and responsive, hierarchically assembled nanomaterials.

Linking experimental findings and theoretical insights on the mechanochemical synthesis of PbTe quantum dots: The effect of ethylene glycol

It is provided a new pathway for obtaining the formation of small dimensional PbTe nanostructures during milling, including quantum dots (QDs). It is possible via the addition of ethylene glycol (EG) which is the key factor to decide the final morphology and size of small dimensional PbTe nanostructures. Therefore, in this work, the effects of EG, as a process control agent (PCA), on the growth mechanisms of PbTe QDs are experimental and theoretically investigated. To achieve this goal, the behavior between EG and inorganic PbTe interface interactions is explored via density functional theory (DFT). The occurrence of PbTe is detected by using X-ray diffraction technique and the mechanical kneading suppression is verified through electron microscopy results. The formation of rounded and quasi faceted PbTe QDs are ruled by structural-defect and imperfect oriented attachment mechanisms respectively, which are strongly evidenced by high-resolution transmission electron microscopy. Interactions between EG and low-index surfaces are modeled by dispersion-corrected DFT calculations. Through the electrostatic potential mapped on the van der Waals isosurfaces, adsorption modes of the selected PCA on the PbTe surface are proposed, allowing rationalizing the facets exposed by the PbTe QDs after the surface treatment. Changes induced by the EG molecule, as PCA, are rationalized in terms of surface energy. Interactions with the PbTe surfaces stabilize the (100) facet, while destabilize the (111) facet. Wulff constructions support the formation of particles, in the nanometric scale, with cubic or cubic with rounded edges.

Tailoring of nonlinear optical and optical limiting performance through morphology: PbTe nanostructures in liquid and solid-state matrice

Advances in nanotechnology have provided opportunities to precisely control the morphology of nanostructures and the ability to explore their structure–property relationships. In this work, well-defined PbTe nanostructures with different morphologies were prepared by a one-step microwave synthesis process. The synthesized PbTe nanostructures were incorporated into solid-state silica gel glass matrices by a facile sol-gel approach for application as optical limiters. Nonlinear optical (NLO) and optical limiting (OL) properties were measured by 532-nm laser pulses with a pulse duration of 35 ps to understand the relationship between the NLO properties and the morphology of six PbTe nanostructures (i.e., nanosheets, nanorods, particle assemblies, hoppercubes, nanocubes, and nanoflowers). The PbTe nanostructures had notably different NLO and OL properties, which strongly correlated with the structural characteristics both in liquid and gel glass matrices. The NLO mechanism was also explored and attributed to excited state absorption, which relates to the size and morphology of the nanostructures. The PbTe particle assemblies had the strongest NLO response under laser irradiation, whereas the PbTe nanocubes had the weakest response, both in liquid and a solid-state gel glass matrices. Importantly, a large OL effect was observed for PbTe particle assemblies doped into silica gel glasses, where the OL threshold surpassed that of previously reported semiconductor nanocrystals. This result suggests these materials can be considered as potential candidate for practical applications in the fields of nonlinear optics. Our work provides insights into the morphology dependence of NLO properties and a strategy to optimize the performance of nanostructures through structural design.

Synergistic effect of morphology and Co+2/Co+3 ratio on supercapacitor performance of Co3O4/vertical graphene nanosheets binder-free hybrid electrodes

Cobalt oxide (Co3O4) nanostructures decorated vertical graphene nanosheets (VGN) based hybrid electrodes are synthesized to fabricate binder-free high-performance supercapacitors. Tuning of microstructure, morphology, and stoichiometry of Co3O4 nanostructures is endeavoured by growing them in an oxygen medium using the pulsed laser deposition (PLD) technique. The variation in background oxygen pressure transformed the growth morphology of Co3O4 nanostructures from smooth film to nano-particulate caterpillar, flower, and cloud-like. Additionally, the variation in background oxygen pressure significantly influences the Co+2/Co+3 ratio. Moreover, the morphology variation led to a significant change in electrochemical active surface area (ECSA), and the electrochemical impedance characteristics varied from highly capacitive to nearly diffusive nature. These Co3O4/VGN hybrid electrodes exhibited an areal capacitance value of 32 mF/cm2 (1900 F/g) @ 20 mV/s with cyclic stability of 87 % after 3000 charge-discharge (CD) cycles in 1 M KOH electrolyte. Herein, a correlation between morphology, ECSA, and Co+2/Co+3 ratio with areal capacitance values is established. Finally, an asymmetric coin-cell device is fabricated using the Co3O4/VGN as a positive electrode and oxygenated VGN as a negative electrode, respectively. The coin-cell device exhibited a 4 mF/cm2 capacitance with energy and power densities of about 1.8 μWh/cm2 and 218.8 μW/cm2, respectively. Additionally, the coin-cell device displayed excellent cyclic stability of 92% after 5000 CD cycles. The potential utilization of this device is demonstrated by lighting an LED.

Nanosecond Laser Fabrication of Novel Micro-/Nanostructured Metal Surfaces: A Dual-Functional Supersurface Combining Antireflectivity and Superhydrophobic Properties.

The research and applications in the field of micro/nano surface manufacturing are progressively shifting their focus toward multifunctional surfaces. In practical applications, objects often need to operate under demanding environmental conditions, and single-function surfaces have inherent limitations in terms of performance, adaptability, and longevity. In this paper, a micro-/nanolayered structural strategy with dual functions of ultrahigh antireflective properties and superhydrophobicity was created on the surface of titanium alloy by using nanosecond pulsed laser processing, and two structural modes of periodic honeycomb and lattice with controllable shapes were designed. In addition, the morphology and formation mechanism of multilevel micro-/nanostructures were investigated in depth, combining laser texturization and silanization of substrate microstructures. The effects of the micro-/nanostructured morphology on the reflection and wettability properties were evaluated with different pulse widths and lateral overlap index. This study also demonstrated that water droplets exhibit excellent bouncing and rolling behavior on superhydrophobic surfaces, further verifying the excellent hydrophobic properties of the prepared samples. Furthermore, in addressing the challenges of susceptibility to dust contamination and performance degradation in extreme environments associated with antireflective surfaces, a series of durability and mechanical stability tests were conducted on controllability periodic micro-/nanostructured surfaces. Successfully meeting this challenge will open up great potential and opportunities for significant improvements in equipment performance and stable operation under extreme operating conditions.

NEW ZINC-BONE APATITE FILMS SHOW ANTI-TUMOUR EFFICACY AGAINST BONE METASTASES IN VITRO

Decreasing the chance of local relapse or infection after surgical excision of bone metastases is a main goals in orthopedic oncology. Indeed, bone metastases have high incidence rate (up to 75%) and important cross-relations with infection and bone regeneration. Even in patients with advanced cancer, bone gaps resulting from tumor excision must be filled with bone substitutes. Functionalization of these substitutes with antitumor and antibacterial compounds could constitute a promising approach to overcome infection and tumor at one same time. Here, for the first time, we propose the use of nanostructured zinc-bone apatite coatings having antitumor and antimicrobial efficacy. The coatings are obtained by Ionized Jet Deposition from composite targets of zinc and bovine-derived bone apatite. Antibacterial and antibiofilm efficacy of the coatings is demonstrated in vitro against S. Aureus and E. Coli. Anti-tumor efficacy is investigated against MDA- MB-231 cells and biocompatibility is assessed on L929 and MSCs.A microfluidic based approach is used to select the optimal concentration of zinc to be used to obtain antitumor efficacy and avoid cytotoxicity, exploiting a custom gradient generator microfluidic device, specifically designed for the experiments. Then, coatings capable of releasing the desired amount of active compounds are manufactured. Films morphology, composition and ion-release are studies by FEG- SEM/EDS, XRD and ICP. Efficacy and biocompatibility of the coatings are verified by investigating MDA, MSCs and L929 viability and morphology by Alamar Blue, Live/Dead Assay and FEG-SEM at different timepoints. Statistical analysis is performed by SPSS/PC + Statistics TM 25.0 software, one-way ANOVA and post-hoc Sheffe? test. Data are reported as Mean ± standard Deviation at a significance level of p <0.05.Results and Discussion. Coatings have a nanostructured surface morphology and a composition mimicking the target. They permit sustained zinc release for over 14 days in medium. Thanks to these characteristics, they show high antibacterial ability (inhibition of bacteria viability and adhesion to substrate) against both the gram + and gram – strain.The gradient generator microfluidic device permits a fine selection of the concentration of zinc to be used, with many potential perspectives for the design of biomaterials. For the first time, we show that zinc and zinc-based coatings have a selective efficacy against MDA cells. Upon mixing with bone apatite, the efficacy is maintained and cytotoxicity is avoided. For the first time, new antibacterial metal-based films are proposed for addressing bone metastases and infection at one same time. At the same time, a new approach is proposed for the design of the coatings, based on a microfluidic approach. We demonstrated the efficacy of Zn against the MDA-MB-231 cells, characterized for their ability to form bone metastases in vivo, and the possibility to use nanostructured metallic coatings against bone tumors. At the same time, we show that the gradient-generator approach is promising for the design of antitumor biomaterials. Efficacy of Zn films must be verified in vivo, but the dual-efficacy coatings appear promising for orthopedic applications.

Flow-induced fabrication of ZnO nanostructures in pillar-arrayed microchannels.

The emergence of microfluidic devices integrated with nanostructures enables highly efficient, flexible and controllable biosensing, among which zinc oxide (ZnO) nanostructure-based fluorescence detection has been demonstrated to be a promising methodology due to its high electrical point and unique fluorescence enhancement properties. The optimization of microfluidic synthesis of ZnO nanostructures for biosensing on chip has been in demand due to its low cost and high efficiency, but still the flow-induced growth of ZnO nanostructures is not extensively studied. Here, we report a simple and versatile strategy that could manipulate the local flow field by creating periodically arranged micropillars within a straight microchannel. We have explored the effects of perfusion speed and flow direction of seed solution, localized flow variation of growth solution and growth time on the morphology of nanostructures. This provided a comprehensive understanding which governs nanostructure fabrication controlled by flow. The results demonstrated that localized flow in microfluidic devices was essential for the initiation and growth of zinc oxide crystals, enabling precise control over their properties and morphology. Furthermore, a model protein was used to demonstrate the intrinsic fluorescence enhancement of ZnO nanostructures as an example to reveal the morphology-related enhancement properties.

Chemically synthesized poly(3,4-ethylenedioxythiophene) conducting polymer as a robust electrocatalyst for highly efficient dye-sensitized solar cells.

Chemically synthesized PEDOT (poly(3,4-ethylenedioxythiophene)) nanomaterials, with various nanostructured morphologies as well as different intrinsic electrical conductivities and crystallinities, were compared as electrocatalysts for Co(III) reduction in dye-sensitized solar cells (DSSCs). Electrochemical parameters, charge transfer resistance toward the electrode/electrolyte interface, catalytic activity for Co(III)-reduction, and diffusion of cobalt redox species greatly depend on the morphology, crystallinity, and intrinsic electrical conductivity of the chemically synthesized PEDOTs and optimization of the fabrication procedure for counter electrodes. The PEDOT counter electrode, fabricated by spin coating a DMSO-dispersed PEDOT solution with an ordered 1D structure and nanosized fibers averaging 70 nm in diameter and an electrical conductivity of ∼16 S cm-1, exhibits the lowest charge transfer resistance, highest diffusion for a cobalt redox mediator and superior electrocatalytic performance compared to a traditional Pt-counter electrode. The photovoltaic performance of the DSSC using chemically synthesized PEDOT exceeds that of a Pt-electrode device because of the enhanced current density, which is directly related to the superior electrocatalytic ability of PEDOT for Co(III)-reduction. This simple spin-coated counter electrode prepared using cheap and scalable chemically synthesized PEDOT can be a potential alternative to the expensive Pt-counter electrode for cobalt and other redox electrolytes in DSSCs and various flexible electronic devices.

Polytypic metal chalcogenide nanocrystals.

By engineering chemically identical but structurally distinct materials into intricate and sophisticated polytypic nanostructures, which often surpass their pure phase objects and even produce novel physical and chemical properties, exciting applications in the fields of photovoltaics, electronics and photocatalysis can be achieved. In recent decades, various methods have been developed for synthesizing a library of polytypic nanocrystals encompassing IV, III-V and II-VI polytypic semiconductors. The exceptional performances of polytypic metal chalcogenide nanocrystals have been observed, making them highly promising candidates for applications in photonics and electronics. However, achieving high-precision control over the morphology, composition, crystal structure, size, homojunctions, and periodicity of polytypic metal chalcogenide nanostructures remains a significant synthetic challenge. This review article offers a comprehensive overview of recent progress in the synthesis and control of polytypic metal chalcogenide nanocrystals using colloidal synthetic strategies. Starting from a concise introduction on the crystal structures of metal chalcogenides, the subsequent discussion delves into the colloidal synthesis of polytypic metal chalcogenide nanocrystals, followed by an in-depth exploration of the key factors governing polytypic structure construction. Subsequently, we provide comprehensive insights into the physical properties of polytypic metal chalcogenide nanocrystals, which exhibit strong correlations with their applications. Thereafter, we emphasize the significance of polytypic nanostructures in various applications, such as photovoltaics, photocatalysis, transistors, thermoelectrics, stress sensors, and the electrocatalytic hydrogen evolution. Finally, we present a summary of the recent advancements in this research field and provide insightful perspectives on the forthcoming challenges, opportunities, and future research directions.

Understanding the morphological evolution of anodic tantalum oxide nanostructures in acidic medium

This paper shows the effect of anodizing conditions on the chemical composition and morphology of ATO nanostructures, and discusses the kinetics of ATO growth by applying various growth models.

Morphology-controlled synthesis of novel nanostructured Li4P2O7 with enhanced Li-ion conductivity for all-solid-state battery applications.

Mechanical stiffness of oxide-type solid-electrolytes is a major drawback which has hindered their practical application in all-solid-state Li-ion batteries to date. Despite their enhanced structural and electrochemical stabilities, lack of deformability of fast-ion conducting oxides impedes the integration of these materials in bulk-type solid-state cells. Deformable solid-electrolytes such as sulfides, on the other hand, lack sufficient electrochemical stability in contact with conventional cathodes. This has recently triggered a search for new materials that combine high ion-conductivity, deformability and sufficient electrochemical stability. Here, we report the synthesis of a novel form of Li4P2O7 that can be densified by cold-pressing and possesses an ion conductivity that is two orders of magnitude higher than conventional Li4P2O7 phases. The material is synthesized by a combination of microwave synthesis and chemical lithiation and adopts a nanostructured morphology with a small amorphous component. The material is electrochemically stable at voltages >5 V vs. Li+/Li, which suggests safe use with high-voltage cathodes. The newly-synthesized material is therefore a bulk, deformable analogue of LiPON, with comparable ion conductivity and phase stability. This research highlights the potential of using novel low-temperature synthetic routes to control the morphology and enhance the electrochemical performance of conventional functional materials.

Copper Surface Treatment with deep UV Ultrafast Laser for Improved Photocathode Photoemissive Properties

Cesium Telluride (Cs2Te) constitutes today the photoemissive semiconductor material of choice for electron accelerators due to its high quantum efficiency (QE) in the deep ultraviolet (DUV) spectral range, and capability to produce high charge over a long operation lifetime. Unfortunately, its chemical instability requires ultra-high vacuum (in the 10-10 mbar range). This inevitably complicates Cs2Te photocathode handling, and increases the overall cost compared to metallic counterparts. Copper photocathodes are alternative candidates, and although they are much more tolerant in terms of vacuum requirements, their use in high average current photo-injectors is limited due to their orders of magnitude lower QE (around 10-5 per unit). With the development of nanophotonics, plasmonic phenomena can now be exploited to tailor a new range of effects in the photoemission process. In this work, we focus on direct laser fabrication of nanostructures for plasmonic electric-field enhancement on copper, and study their potential for enhancing the quantum yield. We develop a methodology to fabricate the nanostructures by irradiating the Cu surface with 257 nm femtosecond pulses, well above copper’s work function. We directly obtained nanostructures 100-200 nm, matching the plasmonic resonance for photoinjector wavelengths. The study is accompanied by a parametric scan allowing to obtain the optimal laser machining parameters, and the analysis of the nanostructure morphologies obtained.

Plasma-based post-processing of colloidal nanocrystals for applications in heterogeneous catalysis.

This review summarizes the work on the use of plasmas to post-process nanostructures, in particular colloidal nanocrystals, as promising candidates for applications of heterogeneous catalysis. Using plasma to clean or modify the surface of nanostructures is a more precisely controlled method compared to other conventional methods, which is preferable when strict requirements for nanostructure morphology or chemical composition are necessary. The ability of plasma post-processing to create mesoporous materials with high surface areas and controlled microstructure, surfaces, and interfaces has transformational potential in catalysis and other applications that leverage surface/interface processes.

2D organic nanosheets of self-assembled guanidinium derivative for efficient single sodium-ion conduction: rationalizing morphology editing and ion conduction.

The resurgence of interest in sodium-ion batteries (SIBs) is largely driven by their natural abundance and favourable cost, apart from their comparable electrochemical performance when compared with lithium-ion batteries (LIBs). The uneven geographic distribution of the raw materials required for LIBs has also contributed to this. The solid-state electrolyte (SSE) is typically one of the vital components for energy storage in SIBs and for achieving high electrochemical performances. SSEs are preferred over liquid electrolytes primarily due to their enhanced safety and stability, apart from the option of achieving higher energy density. A single sodium-ion selective conductor minimises dendrite formation and cell polarisation, among many other benefits over binary ionic conductors in battery operation. Here, we demonstrate the first example of a sulfonated supramolecular organic two-dimensional (2D) nanosheet as a novel class of single sodium-ion conductors prepared from the self-assembly of a functionalised guanidinium ion (AD-1). Solvent-assisted exfoliation of the bulk powder in water yielded nanosheet morphology, whereas nanotube morphology was achieved in isopropanol (IPA). In contrast, self-assembly with systematic water/IPA solvent ratio variations produced marigold, sunflower, and nanorod morphologies. Thermodynamic parameters, crystallinity, elemental composition, and varying natures of hydrogen bonding in five distinct morphologies were determined using microscopic and spectroscopic studies. The single Na+ conducting properties of each morphology are correlated in terms of morphology, crystallinity, and the solvent used to achieve that specific morphology. Importantly, with high crystallinity and directional ion channels, 2D nanosheet morphology exhibits the highest single Na+-ion conductivity of 3.72 × 10-4 S cm-1 with an activation energy of 0.28 eV, showing a moderately high Na+-ion transference number of 0.83 at room temperature without incorporating any additional sodium salts and organic solvents. This report is believed to be the first to show the significance of nanostructure morphologies in achieving high single-Na+-ion transport.